I suspect it will take a long time before a stalemate is clearly reached. Putin has no incentive to negotiate in good faith until there is one - and even then he could renege right after signing, so why trust him? Ukraine needs to take the lead on these negotiations. The world needs to give Ukraine leverage in the form of more sanctions. And it will be that leverage that will hold Putin to his agreements this time. Obviously to him the Budapest Memorandum was just a piece of paper, and Russia's word isn't worth anything. Hopefully the rest of the world will back up Ukraine and not dictate from the sidelines for a premature relaxation from sanctions.